Nonpolymeric sulfonated hydroquinone antistain agents



United States Patent NONPOLYMERIC SULFONATED HYDRO- QUINONE ANTISTAIN AGENTS John R. Thirtle and Frederick C. Duennebier, Rochester,

N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application December 15, 1951, Serial No. 261,914

6 Claims. (Cl. 95-7) This invention relates to color photography and particularly to a method for preventing the formation of color fog or stain in photographic emulsions.

The method of color photography in which colorforming or coupler compounds combine with the development product of aromatic amino photographic developers to produce dyes is well known. The color formers or couplers may be added directly to the emulsion layers or may be incorporated in the developing solution as described in Fischer U. S. Patent 1,102,028, granted June 30, 1914, or they may be incorporated in a waterpermeable medium which is insoluble in the carrier for the sensitive silver salt as described in Mannes and Godowsky U. S. Patent 2,304,940, December 15, 1942, and Jelley and Vittum U. S. Patent 2,322,027, granted June 15, 1943.

A difiiculty frequently encountered in these processes is the formation of color fog or stain. When the exposed material is developed in a color-forming developer, dye fog is frequently formed in the emulsion layer. This is because the developing agent has been oxidized to some extent by the action of the air and the oxidized developertends to couple with the color-forming compound at places in the photographic material where no silver image is produced. It is well known that in these processes the dye should be formed only where the silver halide is reduced to metallic silver, thereby oxidizing the developing agent to a form which couples with the color former. Once the developing agent is oxidized, it couples immediately with the color former whether a photographic image is present or not. Aerial oxidation of the developer or oxidation by means other than the photographic image therefore converts the developer to a form which will immediately react with the color former to produce a color fog or stain. This eifect is especially noticeable in materials having couplers incorporated in the sensitive layer since there is no coupler in the developing solution to react with any developing agent which is oxidized by the action of the air. Fog or stain arising from these causes is not readily controlled by the same procedures used to control silver fog.

The control of color fog or stain by incorporating various compounds in photographic emulsions has been described in Weissberger and Vittum U. S. Patent 2,356,486, August 22, 1944, and Vittum and Wilder U. S. Patent 2,360,290, October 10, 1944. However, the use of these simple reducing agents for preventing or controlling color fog or stain has a distinct disadvantage in that they have a tendency to wander from the areas in which they have been placed into other areas of the photographic composition where they have harmful effects. In certain color processes the compounds are placed in the area of the emulsion containing the coupler and act on it to produce undesired elfects as will be explained more fully hereinafter.

Antistain agents for direct incorporation in photographic emulsion layers must fulfill certain requirements such as the following:

1. They must be easily compatible with and substantially non-difiusing in the colloid of the photographic layer.

2. They must have a strong enough reducing action so that they react rapidly with the oxidized color developer. Their action as antistain agents presumably depends upon their ability to reduce the oxidized developer formed in the highlight areas of the image.

3. They must be of such a nature that they do not give rise to highly colored oxidation products, so that when the material containing them is put through an 8 benzyl radical or oxidizing bath such as a silver bleach bath they do not themselves give rise to stain.

It is, therefore, an object of the present invention to provide antistain agents which are easily compatible with and non-difiusing in the colloid of the photographic layer in which they are incorporated. A further object is to provide antistain agents which are non-diffusing in the photographic layer and which are strong enough reducing agents to react rapidly with oxidized color developer. A further object is to provide antistain agents which do not form highly colored oxidation products when the material containing them is put through an oxidizing bath. Other objects will appear from the following description of our invention.

These objects are accomplished by the use in an emulsion or other layer of a photographic material of a non-polymeric alkyl hydroquinone having a sulfonic acid group in its molecule and being non-dilfusing in the colloid of the layer in which it is incorporated. Where the term alkyl is used in the claims, it is to be understood that both simple alkyl and aralkyl substituents are included.

The compounds which we propose to use have the structure "ice H in which R represents hydrogen or an alkyl or aralkyl group and R represents an alkyl, aralkyl or acylamino group. The alkyl group may be a simple alkyl group such as methyl, ethyl, propyl, butyl or amyl or a longchain alkyl group such as undecyl, hexadecyl or octadecyl. The aralkyl group may be a benzyl or substituted phenethyl, phenylpropyl, etc. The compounds are sulfonated by incorporating a sulfonic acid radical either in the hydroquinone ring or in one of the substituent radicals attached to the hydroquinone nucleus. If the compound is to be non-migratory as, for example, when its action must be restricted to one layer of a multi-layer material, R must be larger than C10 when R is hydrogen. If the wandering of the antistain agent does not need to be restricted to a single emulsion layer, R and R may be lower alkyl or aralkyl groups. The compounds are incorporated ordinarily as a soluble salt, such as the sodium, potassium, lithium or ammonium salt.

Antistain agents useful according to our invention are:

calcium-000 0 2-{3-(3-[3-(4-amyl-x-sulfophenoxy -benzamido]-benzamido}- ethyl}-hydroquinone sodium salt) 2,5 bis{N-{3-[2,4 diamylphenoxy)- 5 -(2 sultobenzamido)- beiitzftmido]-plieny1}carbamy1methy1}-hydroquinone (sodium 59.

OH -CHzSOaNa /Hs sea-CHE:

5-sec.-octadecyl-2- (2-su1fo-terti;:buty1) hydroquinone (sodium 2,5-b1s{fi- [3- p-tert.-amy1phenoxy) -x-sulfo] -benzamidoethyl}hydroquinone (sodium salt) 6. SOaNS on NHOOQ NH 0-? OsNa l n QUEER-t.

2-[2'-(2",4"-dl-tert.-amylphenoxy)-5-(3",5f-disulfo-benzamido)-benzamido]-hydroquinone (sodium salt) sec.- C 11112 H Potassium sec.-undecyl-hydroquinone-x-sulfonate n-CmH Potassium n-hexadecyl-hydroquinone-x-sulfonate S O aK H Potassium n-octadecyl-hydroquinone-x-sulfonate Potassium Z-methyl-5-sec.-octadecyl-hydroquinone-x-sulfonate on soma omonmnoo CONHCHQC (LO-0.11114; l-CaHu-Q n S OaK Potassium-3-benzy1-x-su1fonate son: amour-Gonzl on Potassium-3-p-ethylbenzyl-x-sulfonate S O 3N8 Potassium-3-(p-benzyl)-benzyl-x-sulfonate The antistain agents of our invention are especially useful in emulsion layers containing water-soluble, nondifiusing color couplers of the type described in Fischer U. S. Patent 1,102,028. In these coatings the hydrophilic antistain agents offer the advantage that they can be added directly to the emulsion melt befort coating without requiring the preparation of a dispersion. Our antistain agents may also be used in emulsions of the type described in Mannes and Godowsky U. S. Patent 2,304,940, and Jelley and Vittum U. S. Patent 2,322,027 where the coupler is present in a dispersed hydrophobic solvent. In certain of these systems the presence of the antistain agent in the dispersed phase causes a reduction in the stability in the developed dye image. This situation exists in certain of the layers containing cyan and yellow-forming couplers. The presence of an antistain agent such as diamyl or dioctyl hydroquinone in these layers causes a slight decrease in the light-fastness of the dye images. On the other hand, in emulsion layers of this type containing magenta-forming couplers such as pyrazolones the stability is improved by the presence of an oil-soluble antistain agent such as dioctyl hydroquinone in the dispersed phase. In this case, the residual coupler is made more resistant to print-out by light and yellowing by heat. Thus, in coatings of this type in which maximum dye stabilities are desired, distinct advantages are gained by the use of the hydronhilic antistain agents in some of the layers, e. g. the yellow and cyan layers, and oil-soluble hydrophilic antistain agents in other layers, e. g. the magenta layer.

The antistain agents of our invention may also be used in non-sensitive overcoating or filter layers such as the colloidal silver interlayer.

The incorporation of our antistain agents in an emulsion of the type of Fischer U. S. Patent 1,102,028 is illustrated by the following examples.

EXAMPLE 1 brought to 200 cc. To this solution was then added a agent.

EXAMPLE 2 Six-tenths gram of the coupler, 1-hydroxy-4-chloro-2- {B-{4'-[2"-(2"', 4'-diamyl)-phenoxy-5"-(3"', dichlorosulfonyl) benzamido] benzamido} phenethyl} naphthamide, was dissolved in a mixture of 3 cc. of 95% ethanol and 1.5 cc. of a 20% sodium hydroxide solution. The resulting clear solution was added to 40 cc. of 2% gelatin solution, and the pH of the mixture was adjusted to 7.0 by the slow addition of 2.5% citric acid solution. The neutralized coupler solution was added to 30 cc. of melted positive-type emulsion. The antistain agent, 0.1 g. of potassium n-hexadecylhydroquinone-xsulfonate, was dissolved in 2.5 cc. of water and this solution was added to the coupler-emulsion mixture before coating on a suitable support. The resulting coating gave a clear cyan dye image on color development with distinctly lower stain than was obtained with a similar coating containing no antistain agent.

The incorporation of our antistain agents in an emulsion of the type of those described in Jelley and Vittum U. S. Patent 2,322,027 is illustrated by the following example.

EXAMPLE 3 One gram of the coupler N-[4-(benzoylacetamino)- benzenesulfonyl]-N-('y-phenylpropyl)-p toluidine, was dissolved at 130 C. in 3 cc. of di-n-butylphthalate. This hot solution was poured with stirring into a solution containing 18 cc. of gelatin solution, 2 cc. of water, and 2 cc. of 10% alkanol B (sodium triisopropylnaphthalene sulfonate). The whole mixture was then passed several times through a colloid mill. The resulting fine dispersion was then added, at 40 C., to 50 cc. of a melted positive-type emulsion. The antistain agent, e. g., 0.1 g. of potassium sec.-undecylhydroquinone-x-sulfonate, was dissolved in a minimum amount of water (about 2 cc.) and added to the coupler-emulsion mixture before coating on a suitable support. The resulting coating gave a bright yellow dye image on color development, and showed a marked reduction in stain over a similar material prepared without the antistain agent.

A complete three-color coating may be prepared as follows EXAMPLE 4 A multi-layer coating was prepared as follows: On the support was coated a red-sensitized emulsion layer containing a cyan coupler prepared as in Example 2. Over this was coated a thin gelatin interlayer, and then a layer of green-sensitized emulsion containing the magenta coupler, 1-[(p-tert.butylphenoxy)-phenyl]-3-[a-p tert.- butylphenoxy) -propionyl-amino]-5-pyrazolone, and the antistain agent di-isoctylhydroquinone. This magenta layer was prepared according to the general methods given in U. S. 2,360,290. Next was coated a yellow filter layer containing colloidal silver, and finally an emulsion layer containing a yellow coupler prepared as in Example 3 above. On normal color development, this multi-layer coating gave excellent color prints with a lower level of stain in the highlights. The stability to light of the color prints was found to be greatly superior to that obtained with a material containing the antistain agents of U. S. 2,360,290 in all of the emulsion layers.

The compounds of our invention are prepared by treating a hydroquinone with a suitable unsaturated hydrocarbon, sulfonated or not. If the unsaturated hydrocarbon is unsulfonated the resulting compound is sulfonated, or oxidized to a quinone which is then sulfonated by addition of sodium bisulfite."-- -The-following example is typical.

Potassium sec. undecylhydroquinone monosulfonate sec.-undecylhydroquinone OH A mixture of 77 g. (0.5 mole) of undecene-l and 55 g. (0.5 mole) of hydroquinone was stirred in a 500 cc. flask equipped with an air condenser and thermometer and heated by an oil bath. The vigorously stirred mixture was treated at 200 C. with 68 g. (0.5 mole) of zinc chloride. The temperature was held at 200-210 C. for 3% hours. The mixture was allowed to cool and the catalyst was hydrolyzed with cc. of 10% hydrochloric acid. The oil layer was washed several times with hot water until the wash water was neutral. The oil was then taken up in 200 cc. of ether and Washed twice with water. After filtration and evaporation, the residual oil was twice fractionally distilled under vacuum. The final product weighed 31.5 g. (24%) 170.5 163-166 C.

sec.-undecylqulnone CH: CH; (BHKCHzhCH: NazCnOJHaO CH(CH2)ICH3 A solution of 26.4 G. (0.1 mole) of sec.-undecylhydroquinone in 350 cc. of acetone and 50 cc. of water was stirred at 0 C. while 50 cc. of concentrated sulfuric acid was added dropwise. The solution was cooled at 5 to 0 C. while 15 g. (0.05 mole) of sodium dichromate dihydrate in 50 cc. of water was added dropwise over a period of one-half hour. The reaction mixture was stirred for one-half hour longer, then was allowed to stand for one hour (convenience). On dilution with 500 cc. of water the solid dissolved and the quinone separated as an oil. The latter was extracted into ether, dried over sodium sulfate, concentrated, and distilled. The quinone boiled at 122-5 C. at 0.5 mm. and amounted to 19.7 g. (75.2%

sec.-Undecylhydroquinonemonosulfonate potassium salt OH OH NaOaS KOaS on on A buffered bisulfite solution containing 0.21 g. (0.0025 mole) of sodium acetate (anhyd.), 0.037 cc. of glacial acetic acid, 1.09 g. (0.0105 mole) of sodium bisulfite and 6.5 cc. of water was stirred at room temperature while a solution of 2.6 g. of sec.-undecylquinone in 15 cc. of ethyl alcohol was added dropwise over a period of 1 hour.

The reaction mixture was stirred for 1 hour longer and then concentrated to dryness under vacuum on a steam bath. The residue was dissolved in 10 cc. of water, and 2.0 g. of potassium chloride was added. The semi-solid potassium salt of the sulfonic acid separated as the potassium chloride dissolved. The aqueous layer was decanted and the residue redissolved in 10 cc. of water and treated with 2.0 g. of potassium chloride. This process was repeated once more. A pasty solid resulted. The solid was dissolved in 15 cc. of acetone, leaving an insoluble inorganic material which was removed by filtration. The clear solution was concentrated on a steam bath, giving a clear resinous material which showed a tendency to harden. The residue was placed in a vacuum desiccator over sulfuric acid overnight, forming hard lumps. The lumps were pulverizzed and replaced in the desiccator for final drying. The yield was 2.2 g. (57.9%) of very hygroscopic power.

In general, the reducing agents of our invention are used in the emulsion or other layer in quantities ranging from 0.07 grams to 4.3 grams per liter of emulsion or gelatin solution. These values are, however, merely illus trative.

In certain cases the antistain agents of our invention may be incorporated in a processing solution such as a prebath, first developer bath, or color-forming developer used with color film which is developed with a primary aromatic amino developing agent. The antistain agents which we propose to use are soluble in alkaline solution and would serve to react with any oxidized developer in the solution but would not diffuse into the film, because of their complex structure.

Our materials are particularly useful with color-forming emulsions coated on paper supports where it is especially important to reduce the minimum or fog densities. This applies both to negative developed paper and to reversal paper as well as to transparency materials. It will be understood that the examples and modifications described herein are illustrative only and that our invention is to be taken as limited only by the scope of the appended claims.

What we claim is:

1. A color-forming photographic element having an emulsion of reduced color fogging tendency, comprising a support having thereon at least a silver halide emulsion layer containing a non-diffusing coupler compound, at least one layer of said element containing a non-diffusing antistain agent of the following structure:

in which R is selected from the class consisting of alkyl groups having 4 carbon atoms, benzamido alkyl groups, benzamido benzamido groups, benzamido benzamido alkyl groups, and benzamido benzamido phenyl carbamyl alkyl roups. g 2. The method of preventing the formation of color fog in a layer of a photographic element containing a non-diffusing color coupler, said element comprising a support having at least one silver halide emulsion thereon, which comprises incorporating in a layer of said element a non-diffusing antistain agent of the following structure:

in which R is selected from the class consisting of alkyl groups having 4 carbon atoms, benzamido alkyl groups, benzamido benzamido groups, benzamido benzamido alkyl groups, and benzamido benzamido phenyl carbamyl alkyl groups, exposing said emulsion and developing it with a primary aromatic amino developing agent.

3. A color-forming photographic emulsion having reduced fogging tendency, comprising a silver halide emulsion having incorporated therein a non-diffusing coupler compound and a water-soluble salt of a non-diffusing antistain agent having the formula:

4. A color-forming photographic emulsion having reduced fogging tendency, comprising a silver halide em-ulsion having incorporated therein a non-difiusing coupler compound and a water-soluble salt of a non-diffusing antistain agent having the formula:

CHzCONH Cs n 5. The method of preventing the formation of color fog in a gelatino-silver halide emulsion which contains a non-difiusing color coupler, comprising incorporating in said emulsion as an inhibitor of color fog, a water-soluble salt of a non-diffusing, non-polymeric alkyl hydroquinone having the structure:

OH SOaH omonmnoo-Q 0 NHCO exposing said emulsion and developing it with a primary aromatic amino developing agent.

6. The method of preventing the formation of color fog in a gelatino-silver halide emulsion which contains a non-diffusing color coupler, comprising incorporating in said emulsion as an inhibitor of color fog, a watersoluble salt of a non-diffusing, non-polymeric alkyl hydroquinone having the structure:

cliaHu CHZCONH- HO- I i exposing said emulsion and developing it with a primary aromatic amino developing agent.

CHzCONH- References Cited in the file of this patent UNITED STATES PATENTS 

1. A COLOR-FORMING PHOTOGRAPHIC ELEMENT HAVING AN EMULSION OF REDUCED COLOR FOGGING TENDENCY, COMPRISING A SUPPORT HAVING THEREON AT LEAST A SILVER HALIDE EMULSION LAYER CONTAINING A NON-DIFFUSING COUPLER COMPOUND, AT LEAST ONE LAYER OF SAID ELEMENT CONTAINING A NON-DIFFUSING ANTISTAIN AGENT OF THE FOLLOWING STRUCTURE: 